The present invention relates to liquid storage containers for manually dispensing liquid such as cleaning solutions for contact lenses, and more particularly relates to dispensing nozzles for liquid which must be stored in sterile condition.
Liquids, for example, solutions for cleaning and conditioning contact lenses, have typically been stored in manually squeezable bottles from which the user can repeatedly dispense stored liquids. These liquids must be uncontaminated by microorganisms such as bacteria. Accordingly, expensive bactericidal agents have sometimes been included in the liquid formulation, as for example, in saline formulations for cleaning contact lenses. However, in addition to adding expense, bactericidal agents can cause minor eye irritation and are therefore preferably omitted from formulations for treating contact lenses.
To maintain the sterile condition of such stored liquids, squeezable dispensing bottles have been provided with nozzles including filter membranes which are impermeable to bacteria so that following each dispensing of solution the aspirated air does not carry bacteria into contact with the storage solution. Such nozzles including air filter membranes are described for example in U.S. Pat. No. 4,917,271 and in co-pending patent application Ser. No. 07/406,053, filed Sep. 11, 1989 and entitled LIQUID DISPENSER NOZZLE ASSEMBLY, the disclosure of which is incorporated herein by reference. However, the discharge port itself from which the dispensed liquid is discharged, can be exposed to the ambience and consequent microbial contamination. Such microbial contamination of the discharge port is eliminated in the liquid dispensing nozzles according to the present invention.